Reinforced Fused-Deposition Modeling

ABSTRACT

An apparatus for manufacturing an object includes an extrusion head having an extrusion needle for extruding thermoplastic material associated with one or more fiber strands. The apparatus may further include a turn-table, a more robotic arm for moving the extrusion head and needle, thermoplastic filament and fiber strand spools and thermoplastic filament and fiber strands. A controller is provided for directing the robotic arm, extrusion head and the turn-table. Further, a method for manufacturing an object includes generating a design for the object that substantially satisfies desired structural properties of the object and generating a sequence for extruding one or more beads of thermoplastic material to manufacture the object according to the design, in which the one or more beads of thermoplastic material are associated with one or more fiber strands. The one or more beads of thermoplastic material and the associated one or more fiber strands are then extruded according to the sequence.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/997,319, filed Jun. 4, 2018, which is a continuation of U.S.patent application Ser. No. 15/375,832, filed Dec. 12, 2016, now U.S.Pat. No. 10,011,073, which is a continuation of U.S. patent applicationSer. No. 14/184,010, filed Feb. 19, 2014, which claims the benefit ofU.S. Provisional Patent Application No. 61/766,376, filed Feb. 19, 2013,each of which is entirely incorporated herein by reference. If there areany contradictions or inconsistencies in language between thisapplication and the case that has been incorporated by reference thatmight affect the interpretation of the claims in this case, the claimsin this case should be interpreted to be consistent with the language inthis case.

FIELD

The present disclosure relates to manufacturing, and, more particularly,to fused-deposition modeling.

BACKGROUND

Fused-deposition modeling is a technique for building athree-dimensional object from a mathematical model of the object. Ingeneral, the object is built by feeding a thermoplastic filament into aheated extrusion head. The heated extrusion head melts and deposits themolten thermoplastic material as a series of beads. Each bead is roughlyspherical or cylindrical in shape—and is much like the toothpaste thatis squeezed from a tube—but much smaller than a grain of rice.Typically, a bead is between 0.001^(th) to 0.010^(th) of an inch thick.When a bead is deposited, it is just slightly above its melting point.After it is deposited, the bead quickly solidifies and fuses with thebeads that are next to and below it.

Perhaps the greatest advantage of fused-deposition modeling is that itcan build an object of any shape. To accomplish this, however, there areconstraints on the sequence in which the beads can be deposited. First,each bead must be supported. In other words, a bead cannot be depositedon air. Therefore, each bead must be deposited on:

-   -   (i) a platform that is not part of the object, or    -   (ii) one or more previously-deposited beads that will be part of        the object, or    -   (iii) a temporary scaffold of support material that is not part        of the object, or    -   (iv) any combination of i, ii, and iii.        Second, when a three-dimensional surface is sealed with beads,        it is no longer possible to deposit a bead inside of that        surface. This is analogous to the situation in which once you        close a box, you can't put anything into the box.

There is a general methodology that is used in fused-deposition modelingthat satisfies these constraints and enables the building of an objectof any shape. The three-dimensional model of the object is modeled asthousands of thin layers in the X-Y plane. Each layer is modeled asthousands of beads and voids. The object is then built, one bead at atime, one layer at a time, only in the +Z direction.

There are, however, costs and disadvantages associated with traditionalfused-deposition modeling.

SUMMARY

One of the disadvantages of traditional fused-deposition modeling isthat the resulting objects are not strong enough for many applications.That is why the objects are often used only as models or prototypes of“real” objects.

Embodiments of the present disclosure address this deficiency bycombining fiber strands with fused-deposition modeling to createfiber-reinforced objects. In general, fiber-reinforced objects are muchstronger than unreinforced objects.

A fiber-reinforced object is built by depositing one or more fiberstrands in association with one or more beads of thermoplastic material.A fiber strand and a bead can be associated in which:

(i) the fiber strand is wholly within the bead, or

(ii) the fiber strand is partially within the bead, or

(iii) the fiber strand is adjacent to the bead, or

(iv) any combination of i, ii, and iii.

A fiber strand and an associated bead can be deposited together orseparately. The fiber strand can be deposited first and then the beadcan be deposited. Alternatively, the bead can be deposited first andthen the fiber strand can be deposited. One fiber strand can beassociated with one or more beads, and one bead can be associated withone or more fiber strands.

The length of a fiber strand can be:

(i) “short,” or

(ii) “medium,” or

(iii) “long.”

A “short-length” fiber strand has a maximum length that is less thantwice the minimum dimension of a bead. The angular orientation of thelongitudinal or neutral axis of a short-length fiber strand associatedwith a bead is generally correlated with the longitudinal or neutralaxis of the bead. Although the ends of a short-length fiber strand canextend beyond the wall of a bead—like a spine on a cactus—a short-lengthfiber strand intersects only one bead and its immediate neighbors. Inaccordance with some embodiments of the present disclosure, short-lengthfiber strands are cut before being deposited, but in other embodimentsthe short-length fiber strands are cut while being deposited.

A “long-length” fiber strand has a length that is approximately equal tothe length of a bead. The angular orientation of a long-length fiberstrand associated with a bead is generally parallel to the longitudinalor neutral axis of the bead. In accordance with some embodiments of thepresent disclosure, long-length fiber strands are cut while beingdeposited, but in other embodiments the long-length fiber strands arecut before being deposited.

A “medium-length” strand has a length longer than a short-length fiberstrand and shorter than a long-length fiber strand. The angularorientation of a medium-length fiber strand associated with a bead isgenerally parallel to the longitudinal or neutral axis of the bead. Inaccordance with some embodiments of the present disclosure, short-lengthfiber strands are cut before being deposited, but in other embodimentsthe short-length fiber strands are cut while being deposited.

In accordance with embodiments of the present disclosure, a bead can beassociated with a fiber strand made of glass, carbon, aramid, cotton,wool, or any other fibrous material.

A bead can be associated with one or more bundles of fiber strands. Abundle of fiber strands can be grouped as a tow, a yarn, or a braid. Thecross section of a bundle of fiber strands can be flat, cylindrical,rectangular, triangular, or irregular. A bundle of fiber strands cancomprise fiber strand made of one or more materials (e.g., glass andcarbon, glass and aramid, carbon and aramid, glass and carbon andaramid, etc.).

An object that is built in accordance with present disclosure cancomprise:

(i) beads that are not associated with a fiber strand, or

(ii) beads that are associated with “short” strands, or

(iii) beads that are associated with “medium” strands, or

(iv) beads that are associated with “long” strands, or

(v) any combination of i, ii, iii, and iv.

In accordance with some embodiments of the present disclosure, thethermoplastic filament comprises one or more fiber strands (or one ormore bundles of fiber strands) prior to being fed into the extrusionhead. In some alternative embodiments, one or more fiber strands (or oneor more bundles of fiber strands) are combined with the thermoplasticmaterial during deposition.

Some embodiments of the present disclosure comprise a plurality ofthermoplastic filaments in which at least one of the filaments does notcomprise a fiber strand and at least one of the filaments does comprisea fiber strand. Furthermore, some embodiments of the present disclosurecomprise a plurality of thermoplastic filaments that each comprise:

(i) a fiber strand of different length, or

(ii) a fiber strand of different material, or

(iii) a fiber strand of different modulus, or

(iv) a different bundle of fiber strands, or

(v) any combination of i, ii, iii, and iv.

Some embodiments of the present disclosure can deposit multiple beadsand fiber strands (or bundles of fiber strands) in parallel.

Some embodiments of the present disclosure can deposit:

(i) a bead of thermoplastic material, or

(ii) a fiber strand, or

(iii) both a bead of thermoplastic material and a fiber strand in asubstantially straight segment whose longitudinal or neutral axis is:

(a) in the X-Y plane and parallel to the X axis, or

(b) in the X-Y plane and parallel to the Y axis, or

(c) in the X-Y plane and at an acute angle to the X axis, or

(d) at a right angle to the X-Y plane, or

(e) at an acute angle to the X-Y plane.

Some embodiments of the present disclosure can deposit:

(i) a bead of thermoplastic material, or

(ii) a fiber strand, or

(iii) both a bead of thermoplastic material and a fiber strand in atwo-dimensional curvilinear segment (e.g., an arc, substantially acircle, a parabola, a sinewave, a spiral, a cissoid, a Folium ofDescartes, a planar spring, etc.) that lies in a plane that is:

(a) parallel to the X-Y plane, or

(b) at a right angle to the X-Y plane, or

(c) at an acute angle to the X-Y plane.

Some embodiments of the present disclosure can deposit:

(i) a bead of thermoplastic material, or

(ii) a fiber strand, or

(iii) both a bead of thermoplastic material and a fiber strand in ahelical segment (e.g., a circular helix, a conical helix, a cylindricalor general helix, a left-handed helix, a right-handed helix, etc.) whoseaxis is:

(a) in the X-Y plane, or

(b) at a right angle to the X-Y plane, or

(c) at an acute angle to the X-Y plane.

The helix can be regular or irregular (like the windings of rope on aspool).

Some embodiments of the present disclosure can deposit:

(i) a bead of thermoplastic material, or

(ii) a fiber strand, or

(iii) both a bead of thermoplastic material and a fiber strand in apolygon (e.g., a triangle, a rectangle, etc.) that lies in a plane thatis:

(a) parallel to the X-Y plane, or

(b) at a right angle to the X-Y plane, or

(c) at an acute angle to the X-Y plane.

The polygon can be regular or irregular, simple or not simple, concaveor non-concave, convex or non-convex.

In general, some embodiments of the present disclosure can deposit beadsof thermoplastic material and fiber strands in many topologies (e.g., atoroid, a cage, etc.).

The fact that some embodiments of the present disclosure can deposit afiber strand at a non-zero angle to the X-Y plane can create a situationin which the general methodology of depositing beads in a strictlayer-by-layer sequence are not possible. Therefore, some embodiments ofthe present disclosure generate an sequence for depositing the beads andfiber strands that is manufacturable. Such sequences can iterativelyprogress in both the +X, −X, +Y, −Y, +Z, and −Z directions.

The location of the fiber strands in the object and their geometry andorientation can affect the structural properties of the object.Furthermore, the structural properties of the object can be predictedbased on the location of the fiber strands in the object and theirgeometry. Therefore, some embodiments of the present disclosure acceptboth a mathematical model of the object and a list of the desiredstructural properties of the object, and generate a design for:

(i) the number of fiber strands in the object, and

(ii) the bundling of the fiber strands in the object, and

(iii) the material of the fiber strands in the object, and

(iv) the Young's modulus of the fiber strands in the object, and (v) thelocation of the fiber strands in the object, and

(vi) the geometry of the fiber strands in the object, and

(vii) the orientation of the fiber strands in the object, and

(viii) an sequence for depositing the beads and fiber strands that:

-   -   (1) attempt to satisfy the desired structural properties of the        object, and    -   (2) can be actually be built.

The latter condition is especially important because there are manyarrangements of fibers that cannot be manufactured usingfused-deposition modeling.

Some embodiments of the present disclosure are capable of depositingsupport material at a location and removing the support material andre-depositing the support material at the same location and of removingthe re-deposited support material. This is to enable the support of abead and fiber strand at one moment and then after the bead has hardenedto enable another bead and fiber strand to be deposited under the first.

Some embodiments of the present disclosure comprise a turntable thatsupports the object while it is built and that spins under the controlof the embodiment's CAD/CAM controller. This facilitates the depositionof circular and helical beads and fiber strands on the object. This alsofacilitates the ability of the embodiments to deposit beads and fiberstrands at any location in the build volume from any approach angle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a front view of manufacturing system 100 in accordancewith the illustrative embodiment of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 depicts a front view of manufacturing system 100 in accordancewith the illustrative embodiment of the present disclosure.Manufacturing system 100 may comprise:

-   -   CAD/CAM controller 101,    -   build chamber 102,    -   turn-table 110,    -   one or more robotic arms 121, each comprising an extrusion head        122 with an extrusion needle 123,    -   thermoplastic filament spool 130-1 and thermoplastic filament        131-1,    -   thermoplastic filament spool 130-2 and thermoplastic filament        131-2, and    -   fiber strand spool 130-3 and fiber strand 131-3.        The purpose of manufacturing system 100 is to build a        three-dimensional object-depicted as object 151 in FIG. 1.

CAD/CAM controller 101 directs the building of object 151 based on amathematical model of object 151. In accordance with the illustrativeembodiment, the mathematical model of object 151 is created with CAD/CAMcontroller 101, but it will be clear to those skilled in the art, afterreading this disclosure, how to make and use alternative embodiments ofthe present disclosure in which the model is created elsewhere andimported into CAD/CAM controller 101.

CAD/CAM controller 101 may comprise a list of the desired structuralproperties of object 151. This list may include, but is not limited to:

1. the desired compression strength characteristics of object 151, and

2. the desired tensile strength characteristics of object 151, and

3. the desired resonance characteristics of object 151.

In accordance with the illustrative embodiment, thermoplastic filament131-1 comprises a continuous tow of 5 low-modulus carbon-fiber strands,and thermoplastic filament 131-2 does not comprise a fiber strand.Thermoplastic filament 131-2 is used as support material in buildingobject 151.

CAD/CAM controller 101 may also comprise a list of the structuralproperties of thermoplastic filament 131-1. This list may include, butis not limited to:

-   -   1. the compression strength of the thermoplastic and tow of        carbon fibers (after deposition and in object 151), and    -   2. the tensile strength of the thermoplastic and tow of carbon        fibers (after deposition and in object 151), and    -   3. the thermal expansion of the thermoplastic and tow of carbon        fibers (after deposition and in object 151), and    -   4. the Young's modulus of the thermoplastic and tow of carbon        fibers (after deposition and in object 151).

CAD/CAM controller 101 may also comprise a list of the structuralproperties of thermoplastic filament 131-2 and/or fiber strand 131-3.

CAD/CAM controller 101 generates a design for object 151 that:

-   -   (1) attempts to satisfy the desired structural properties of        object 151, and    -   (2) a sequence for depositing beads of thermoplastic material        and support material.        The design for object 151 includes, but is not limited to:

(i) the location of fiber strands in the object, and

(ii) the geometry of the fiber strands in the object.

Build chamber 102 is an enclosed environment in which object 151 isbuilt.

Turn-table 110 comprises a platform on which object 151 is built.Turn-table 110 may be driven by a drive mechanism 110-1 that is directedby CAD/CAM controller 101. The drive mechanism 110-1 may comprise amotor arrangement including, but not limited to one or more stepperand/or servo motors. Some embodiments may also include a transmission orgear arrangement for controlled transmission of the rotational movementof the motor(s) to the turn-table 110. The transmission or geararrangement may include without limitation one or more gears, belts,chains, and combinations thereof.

Various embodiments of the drive mechanism 110-1 may be configured torotate the turn-table 110 in clockwise and counterclockwise directionsaround the Z axis under the direction of CAD/CAM controller 101. Thedrive mechanism 110-1, in various other embodiments, may also beconfigured to raise and lower the turn-table 110 in the +Z and the −Zdirections under the direction of CAD/CAM controller 101. In variousother embodiments, the drive mechanism 110-1 may also be configured tomove the turn-table 110 in the +X direction, the −X direction, the +Ydirection the −Y direction, or any combination thereof.

The one or more robotic arms 121 may be configured to place thedispensing end of the extrusion needle 123 at any location in the buildvolume of object 151, from any approach angle. This enablesmanufacturing system 100 to lay fiber strands on the inside an enclosuresuch as a closed sphere through a hole in the enclosure (e.g., sphere)just large enough for extrusion needle 123. The robotic arms 121, invarious embodiments, may be powered by electric motors, hydraulicactuators, or combinations thereof, and configured to provide three ormore axes or degrees of freedom so that the extrusion head/needle canmove in the +X direction, the −X direction, the +Y direction, the −Ydirection, the +Z direction, the −Z direction, or any combinationthereof. In one illustrative embodiment, the robotic arm 121 may beconfigured as a six-axis robotic arm. In another illustrativeembodiment, the robotic arm 121 may be configured as a seven-axisrobotic arm. Any other suitable positioning assembly capable of placingthe dispensing end of the extrusion needle 123 at any location in thebuild volume of object 151, from any approach angle, may be used inplace of the robotic arms 121.

The extrusion head 122 is configured to melt the thermoplastic andextrude the molten thermoplastic (which may partially or wholly containone or more fiber strands) via the extrusion needle 123. Variousembodiments of the extrusion head 122 may define an interior chamber122-1 for receiving the thermoplastic material. The extrusion head 122may include a heater or heating element 122-2 for melting thethermoplastic material within the chamber for extrusion through theextrusion needle in liquid form. The extrusion head 122 may include amotor (not shown) or any other suitable mechanism for pushing thethermoplastic material through the chamber 122-2 and out the extrusionneedle 123. In some embodiments, the extrusion head 122 may also beconfigured with a cutting mechanism 122-4 to cut the one or more fiberstrands to the appropriate length. The cutting mechanism 122-3 mayinclude a blade or other suitable cutting member for cutting the one ormore fiber strands. In one illustrative embodiment, the cuttingmechanism 122-3 may be disposed at the dispensing end or tip 123-1 ofextrusion needle 123.

Extrusion needle 123 may comprise a hollow tube or nozzle having a firstopen end that communicates with the chamber of the extrusion head 122and a second open end (dispending end or tip 123-1) that dispenses thethermoplastic, which may partially or wholly contain one or more fiberstrands. The opening of the tip 123-1 may be circular, oval, square,slotted or any other suitable shape that is capable of extruding thethermoplastic material in a desired cross-sectional shape. In variousembodiments, the extrusion needle 123 may have a length equal to atleast the longest dimension of object 151 so that the tip of 123-1extrusion needle 123 can deposit material at any location in the buildvolume of object 151 from any approach angle.

In operation, according to one illustrative embodiment, one or moremotors may be used for feeding the filament(s) of thermoplastic material131-1, 131-2 (and fiber strand(s) 131-3) into the chamber 122-1 of theextrusion head 122 from the spools 130-1, 130-2, 130-3. Thethermoplastic material entering the chamber 122-1 is melted by theheater 122-2, and extruded from the extrusion head 122 via the extrusionneedle 123. The CAD/CAM controller 101 may control the rate of the oneor more feed motors, the temperature of the heater 122-2, and/or theother process parameters mentioned earlier, so that the thermoplasticmaterial and fiber strand(s) can be extruded in a manner that toattempts to satisfy the desired structural properties of object 151.

Although the manufacturing system, methods, thermoplastic filaments,fiber strands, and other associated elements have been described interms of exemplary embodiments, they are not limited thereto. Rather,the appended claims should be construed broadly to include othervariants and embodiments of same, which may be made by those skilled inthe art without departing from the scope and range of equivalents of thedevice, tray and their elements.

What is claimed is: 1-35. (canceled)
 36. A system for manufacturing atleast a portion of a three-dimensional (3D) object adjacent to asupport, comprising: a source of filament of thermoplastic material, thefilament of thermoplastic material comprising a tow of carbon fibers; asupport for supporting the at least the portion of the 3D object duringmanufacturing; a positioning assembly having a dispensing end fordirecting the filament from the source and into contact with (i) thesupport or (ii) a previously deposited layer of the 3D object adjacentto the support; a heater configured to subject the filament to heating;a cutter for cutting the tow of carbon fibers to generate the at leastthe portion of the 3D object; and a controller operatively coupled tothe cutter, wherein the controller is configured to: (i) direct thefilament from the source toward the dispensing end, and (II) upondirecting the filament toward the dispensing end: a. direct the heaterto heat the thermoplastic material and the tow of carbon fibers, and b.direct the cutter to cut the tow of carbon fibers to generate a portionof the filament, such that the portion of the filament is depositedtowards the support or the previously deposited layer of the 3D objectadjacent to the support, thereby manufacturing the at least the portionof the 3D object.
 37. The system of claim 36, wherein the controller isconfigured to direct the filament from the source toward the dispensingend while the dispensing end is moving along a direction relative to thesupport or the previously deposited layer of the 3D object adjacent tothe support.
 38. The system of claim 37, wherein the controller directsthe dispensing end along the direction relative to the support or thepreviously deposited layer of the 3D object adjacent to the support todeposit a subsequent portion of the 3D object by repeating (i) and (ii).39. The system of claim 36, wherein the controller is configured todirect an additional filament toward the dispensing end for depositionover the support or the previously deposited layer of the 3D objectadjacent to the support.
 40. The system of claim 39, wherein theadditional filament is a thermoplastic filament.
 41. The system of claim36, wherein the source of filament is a spool of filament.
 42. Thesystem of claim 36, wherein the controller is configured to direct anadditional filament inside of the at least the portion of the 3D object.43. The system of claim 36, further comprising: a build chamber having abottom surface and configured to enclose the at least the portion of the3D object during manufacturing; and a drive mechanism configured to movethe support relative to the dispensing end, wherein the drive mechanismis mounted on the bottom surface of the build chamber.
 44. The system ofclaim 36, wherein the controller is configured to control a rate atwhich the filament is directed toward the dispensing end.
 45. The systemof claim 36, wherein the controller Is configured to direct rotation ofthe support around a Z-axis, which Z-axis is perpendicular to an XYplane parallel to a surface of the support.
 46. The system of claim 36,wherein the controller is configured to direct formation of a supportstructure from a source of a thermoplastic filament prior tomanufacturing the at least the portion of the 3D object.
 47. The systemof claim 36, wherein the positioning assembly is a multi-axis roboticarm supporting the dispensing end, wherein the multi-axis robotic arm isconfigured to sequentially deposit the at least the portion of the 3Dobject.
 48. The system of claim 47, wherein the multi-axis robotic armis a six-axis or seven-axis robotic arm.
 49. The system of claim 36,wherein the filament is continuous tow filament.